What Are Brainwaves?

Brainwaves are the patterns of electric pulses made by brain cells (neurons) when they communicate with each other. These pulses are the vibrations made by particles bumping into each other, creating a disturbance and transferring energy. All forms of energy, such as light and sound, are transferred in this way. One pulse is measured as a single positive/negative/neutral vibration called a cycle. The frequency of the cycles within one second is measured in Hertz (Hz). The wave pattern of positive/negative/neutral is represented by a line with peaks and valleys of different heights. The height is called amplitude and represents the strength of the wave. When you see a brainwave plotted on a screen, you are seeing the frequency and amplitude of brainwaves. Brainwave types are categorized by frequency and associated with different types of activity, as described below.

brain waves

Multiple frequencies can be present in the same brain region at the same time. Think of a large sound speaker at a concert. When you look at it closely, or touch it, it is vibrating all over. Rather than producing one sound, there are several sounds coming through the same medium at the same time. Your brain works in the same way, multiple brainwaves are present at the same location at the same time. With neurofeedback, we are training your brain to amplify different brainwave frequencies relative to others, to create a dominant frequency and type of brain activity.



Gamma brainwaves are the highest frequency brainwaves, which pass information rapidly and quietly. They relate to higher processing tasks, learning new material and memory.

gamma brainwave pattern

Gamma is important for the binding of our senses in regards to perception, modulating consciousness and simultaneous processing of information from different brain areas. The brain needs to be quiet to access the subtle gamma wave—healthy rapid eye movement (REM) sleep is correlated with gamma. Creativity and advanced meditation methods can be trained with gamma.


12 - 40 Hz

Beta brainwaves dominate our normal waking state when attention is directed towards cognitive tasks and the outside world. They are involved in alertness and attention, logical thinking and judgement. Having the right amount of beta waves allows us to focus and complete school or work-based tasks easily. Beta brainwaves are further divided into three bands:

beta brainwave pattern

Low Beta (12-15Hz) can be thought of as a relatively calm focus.

Beta (15-22Hz) is associated with an active, alert, problem solving state.

High Beta (22-38Hz) reflects an excited or anxious mind, or very complex thoughts.

When you consume coffee, energy drinks, or other stimulants, your beta activity will naturally increase, as will you heart rate. Continual high beta is not a very efficient way to run the brain, as it takes a tremendous amount of energy. Beta waves are essential for focus, problem solving and socialization, but over-stimulation can amplify stress and/or anxiety and inhibit one’s ability to achieve essential relaxed and rejuvenating states.


8 - 12 Hz

Alpha is the resting state for the brain and bridges our conscious and subconscious minds. Calmness, quiet alertness, mental coordination and mind/body integration occur in alpha states. Alpha waves are prominent in states of deep relaxation and many meditative states.

alpha brainwave pattern

Over-active alpha is found during daydreaming and when we have an inability to focus, while a lack of alpha is associated with high stress and obsessive-compulsive disorder (OCD). Relaxants, some anti-depressants, moderate alcohol consumption and cannabis use can increase alpha waves temporarily. Strengthening one’s ability to produce alpha while quieting other waves, particularly high beta, is a foundational step in brain training.


4 - 8 Hz

This frequency range is prominent in daydreaming and sleep but also in deep meditation. We are withdrawn from external inputs during theta and experience deep and raw emotions. Theta is a light, dreamy state often experienced when we drift off to sleep or wake up naturally.

theta brainwave pattern

It is thought that theta is tightly tied to intuition and creativity as well as our deepest fears. An abundance of theta during waking hours can make people highly suggestible as well as extra sensitive and susceptible to bouts of depression. Training with theta waves is done selectively to encourage creativity and emotional healing.


0.5 - 4 Hz

Delta waves are slow and strong brainwaves present during the deepest levels of relaxation and restorative, healing sleep. Empathy, a strong immune system and the deepest meditations are all associated with delta waves. Delta wave production tends to decrease as we age. When you observe a young child sleeping like a log in a noisy environment, they are in a delta state working healing and growing.

delta brainwave pattern

An inability to get into a deep delta wave sleep hinders our ability to revitalize the brain and rejuvenate the body. Severe brain injuries and cognitive pathologies can be associated with overly active delta waves and an inability to get into high-frequency and active brain states. Depressants and sleep aids are used to try to increase delta wave production/deep sleep. Delta waves are not directly trained in neurofeedback but are helpful to indicate that you fell asleep during your session.

The ability to train to specific frequencies is heavily reliant on the quality of the signal that the electroencephalogram (EEG) can detect. There are many factors that impact quality including muscle movement, electrode placement, and digital signal processing algorithms. A device can produce a graph or number and label it a brainwave measurement without the quality being good enough for training purposes. You can spend your time training “noise” and get sub-optimal results. Sens.ai has gone to great lengths to address these and other factors. This includes a signal quality test at the beginning of every session to ensure your experience is optimal.